


triangles are my favorite shape (three points where two lines meet)

by Crimsoncat



Series: Kinktober 2017 [10]
Category: Marvel Cinematic Universe, The Avengers (Marvel Movies)
Genre: BlackHill Cavalry, F/F, Kinktober 2017, OT3, Polyamory, Strap-Ons, Threesome - F/F/F, smut and feelings
Language: English
Status: Completed
Published: 2017-10-25
Updated: 2017-10-25
Packaged: 2019-01-23 04:20:26
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,708
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12498632
Author URL: https://archiveofourown.org/users/Crimsoncat/pseuds/Crimsoncat
Summary: Natasha and Melinda help Maria recover from a hard and painful mission.





	triangles are my favorite shape (three points where two lines meet)

**Author's Note:**

> I am in love with these three together. They are my newest obsession and as soon as I'm done with kinktober I'll be producing a lot of random fic for them. They're just.. ugh. I love them. Also? I've no idea if there's a ship name for these three, so I'm calling it BlackHill Cavalry. I hope you enjoy this fic, and this triad, as much as I enjoyed writing it.
> 
> Title comes from one of my many musical addictions - Tessellate by Alt-J. It's a fantastic song, and I don't know why it always makes me think of these three but it does.

> Kinktober 2017

Day 10. Threesome (Substitution)

 

 _Triangles are my favorite shape_  
_Three points where two lines meet._  
_Toe to toe, back to back, let's go_  
_My love it's very late._  
_'Til morning comes, let's tessellate._

 

* * *

 

Maria groans as she limps through the apartment and towards the bedroom. She showered before she left SHIELD, unable to stand the feeling of dried blood on her skin for even one more second, but she still just wants to soak in the tub for a few hours. Maria may spend the rest of her life in the tub; she hasn’t decided yet. Everything hurts and her muscles are screaming and, honestly, fuck Hydra.

 

Maria registers their voices halfway down the hallway and she smiles as she pushes open the bedroom door. She opens her mouth, to say hello or maybe ask what they’re doing home when they’re both supposed to be in Washington for three more days. But the words catch in Maria’s throat and she simply stands there for a moment, stunned.

 

“I think we did good,” Natasha murmurs.

 

“So it would seem,” Melinda agrees.

 

There are dozens of candles scattered around the room, and soft music coming from the stereo on the dresser. Both Natasha and Melinda are wearing robes that fall to their knees and their bare skin seems to glow in the candlelight. Maria wonders if they’re wearing anything at all under those robes, and her lungs stall for a moment as she realizes that they probably aren’t.

 

Melinda steps up behind Natasha and she smirks at Maria over Natasha’s shoulder as she lowers her head to mouth along the side of Natasha’s throat. Natasha makes a soft sound of enjoyment as her eyes close and she tilts her head to the side to offer more of her skin to Melinda’s lips. It takes Maria a moment to register that she is the one making the pained strangled sound as she watches them helplessly.

 

Natasha’s eyes open just enough for her to contemplate Maria, still standing in the doorway, and she crooks her index finger. Maria moves slowly, barely aware of the pain in her body as she moves towards her girlfriends. She doesn’t miss the concern that flashes across both of their faces when they see how she’s limping, but it only lasts a moment. (Which tells Maria that they already know exactly what happened and just how bad her injuries are.)

 

Melinda closes her mouth around the pulse point in Natasha’s throat as Maria moves towards them, and she bites down hard. Natasha cries out, her eyes almost rolling back into her head as Melinda sucks at the skin beneath her lips. Natasha groans deeply.

 

“I thought we were going to massage Maria and tease her until she begged.” Natasha’s voice cracks and she gasps when Melinda slowly drags her tongue across the bruise she created.

 

Melinda hums against Natasha’s skin. “We were. But she seems like she’s really enjoying _this._ So maybe we should adjust our plans a bit.”

 

Natasha has to admit that Maria does seem particularly entranced by the sight of them. Which isn’t the least bit surprising; Maria has always enjoyed watching them together. But Natasha had plans that she was looking forward to, dammit. Maria absently licks her lips and Natasha sighs. She cannot deny them this, not when Maria is looking at her like that and Melinda is still nibbling at her neck. “Alright, fine.”

 

Melinda laughs as her hands move to untie Natasha’s robe. “Poor baby.”

 

Maria’s suspicions are quickly confirmed as the robe parts. Natasha is completely naked underneath her robe, which means Melinda will be too. Maria whimpers softly as Melinda’s nails scratch against Natasha’s abdomen and Natasha squirms in her arms. Maria’s hands join Melinda’s on Natasha’s body. Her fingers brushing against Melinda’s as they both stroke Natasha’s skin and she leans over Natasha’s shoulder to kiss Melinda soundly.

 

“Hi,” Maria murmurs into their kiss.

 

Melinda nips at Maria’s bottom lip, apparently in a biting mood. “You need to get off of your feet, sweetheart. Get out of those clothes and go lay down. We’ll join you soon.”

 

“But..” Maria is not someone who pouts, but she is absolutely pouting now.

 

“Maria.” Melinda’s tone leaves no room for argument, and it makes both Maria and Natasha shiver. Melinda smirks. “It’s that kind of night, is it?”

 

Tonight is for Maria. Whatever she wants, whatever she needs, Melinda and Natasha are here to give it to her. Maria has had a very rough and painful couple of days, and they are here to make it better in whatever way that they can. If this is what Maria wants then Melinda is happy to give it to her.

 

"Bed," Melinda says firmly, and Natasha moans quietly at the command in her voice.

 

Maria steps away from them to sit on the edge of the bed, and the way Maria almost collapses tells Melinda that she was right about how much of her pain Maria is trying to hide from them. Natasha stills in her arms, noticing the exact same thing, and Melinda sighs quietly as she tilts her head to kiss Natasha's neck.

 

"We should make her go back to medical," Melinda says against Natasha's skin. She keeps her words pitched low enough that Maria won't hear her.

 

Natasha turns to face her. She presses her face into the crook of Melinda’s neck to cover her low murmur. "She won't go. You know she won't."

 

"Hey, assholes," Maria calls from the bed. "Just because I can't hear you doesn't mean I don't know you're talking about me."

 

Melinda glances to where Maria is stretched out on top of the blankets. She’s removed her jeans and socks but kept her shirt and underwear.

 

Natasha looks over her shoulder incredulously. “Who the hell are you calling an asshole?”

 

“Alright, children, stop it.” Melinda considers the stubborn set to Maria’s jaw, and she knows Natasha is right. The only way they’re going to get Maria back to medical is if they physically force her, which isn’t what Maria needs right now. They saw the results of Maria’s physical and Melinda knows that her injuries are mostly superficial. But. Still. Seeing either of the women she loves in pain is never easy.

 

Melinda grasps Natasha’s hips and turns her back to face the bed. There is an unspoken plea lurking in the sapphire of Maria’s eyes, and Melinda has never been good at saying no to either of them. “You know this means you get to look and not touch, right?” Melinda asks.

 

Maria’s lips part in surprise. “What?”

 

“If you’re in that kind of pain you need to be taking it easy.” Melinda’s eyes flash. “And you couldn’t honestly have thought I would just let that asshole remark go.”

 

Natasha’s quiet snicker is interrupted by a sharp gasp as Melinda tweaks her nipple none too gently. “Unless you want to replace Maria in the ‘tease her until she begs’ scenario you might want to behave, Natasha.” Melinda’s voice is a quiet growl of warning and if Natasha weren’t already soaked that would have done it.

 

Natasha drops her head back onto Melinda’s shoulder and blinks up at her with feigned innocence. “Where’s the fun in behaving?”

 

Melinda considers the women before her and she shakes her head at them. “What am I going to do with you two?”

 

“Have your way with us until we’ve learned how to behave?” Natasha suggests helpfully. The hopeful note in her voice makes Melinda chuckle.

 

“Because that’s worked **so** well in the past,” Melinda sighs with mock exasperation, and her hands stroke across Natasha’s torso even as she begins to move them towards the bed.

 

Maria’s eyes light up as they approach and Melinda smiles. If this is what it takes to lift Maria’s spirits and keep her from thinking about the past couple of days Melinda is happy to oblige. And the speed with which Natasha crawls across the bed towards Maria makes it damn clear that she feels the same. Melinda leaves them to their own devices for a moment while she detours to the dresser, and Natasha slowly kisses her way up Maria’s legs. Maria groans and threads her fingers through Natasha’s hair when she gets within reach.

 

Natasha presses a kiss against Maria’s underwear, making Maria twitch beneath her. “Why are you still wearing so many clothes?” Natasha complains as she bites at Maria’s hip bone.

 

“Because she thinks we don’t realize she’s trying to hide bruises from us,” Melinda offers as she settles next to them on the bed. “Apparently Maria thinks we’re idiots.”

 

“And assholes,” Natasha reminds her. She noses Maria’s shirt out of the way to lick into her bellybutton.

 

Melinda hums thoughtfully as she watches them. “Yes, and assholes. How could I forget.”

 

Maria groans as Natasha continues her torturously slow ascent up Maria’s body. “I just didn't want you to worry more than you had to.”

 

Melinda strokes Maria’s cheek with the back of her hand. “Keep your shirt on if it makes you feel better. But give us a bit more credit than that.”

 

Maria turns her head to press a kiss against Melinda’s knuckles in silent apology as her gaze unfocuses. Melinda glances down to where Natasha has moved on to nibbling along Maria’s side. Melinda leans in a bit further so she can kiss Maria, and Maria gasps into her mouth when Natasha’s teeth bite into her skin.

 

Melinda moves away with a groan. “You both need to shift further up the bed.” Maria and Natasha do as they're told without question, a rare occurrence, and Melinda steps into her favourite harness as they get situated.

 

Natasha crawls up Maria’s body and they watch together as Melinda loses her robe and reaches for the lube. “How did we get so lucky?” Natasha wonders quietly.

 

“I have no idea,” Maria responds, a bit breathlessly. “She’s fucking _gorgeous,_ isn’t she?”

 

Natasha makes a quiet sound of agreement. “Gorgeous and brilliant and all ours.”

 

Melinda watches them as she strokes lube onto the dildo between her legs. Melinda tilts her head at Natasha, and Natasha moves so she’s on her hands and knees above Maria. Melinda rejoins them on the bed, kneeling behind Natasha as she holds Maria’s gaze. Melinda moves her fingers between Natasha’s legs, checking to see how ready she is, and she swears softly.

 

“Our girl is absolutely dripping,” Melinda murmurs, and Maria bites her lip as she shifts beneath them.

 

“Of course I am,” Natasha groans, “have you seen how amazing you look when you’re wearing that thing?” She pushes back against Melinda’s hand, and she whimpers when Melinda listens to the quiet request and begins to fuck Natasha with her fingers.

 

Maria reaches for Natasha, and Melinda makes a _tch_ sound that immediately makes Maria’s hands drop back to the bed. The look she gives Melinda, quietly pained and full of longing, makes Melinda smile wickedly. "No touching,” Melinda reminds her.

 

Maria opens her mouth, to either argue or plead Melinda isn’t sure, and Melinda twists her wrist so she can rub her fingers against Natasha’s g-spot. Natasha almost screams. Her head drops to Maria’s shoulder as she trembles and Maria immediately forgets whatever she was about to say.

 

Melinda grips Natasha’s hip tightly with her free hand. She loves doing this to them; pushing them both to the point of nonverbal desperation. And as Melinda withdraws her fingers, pulling a quiet mewl of need from Natasha, she thinks Maria had it backwards. _She_ is the lucky one here.

 

Melinda grasps the base of the dildo. She slowly drags the tip across Natasha’s lips, and when Natasha tries to push against it Melinda pulls back. Natasha bites at Maria’s shoulder in frustration, and Maria cries out as her hips jerk. Melinda strokes Natasha’s hip with a sound of appreciation. They are both so fucking gorgeous like this.

 

“Please,” Natasha breaks in less than a minute. “Mel, baby, _please.”_

 

“Please what, Nat?” Melinda’s voice is a quiet purr and Maria whimpers desperately.

 

Natasha almost sobs. _“Please.”_

 

“Fuck her, Mel,” Maria answers when it becomes obvious that Natasha can’t. Maria’s words are jagged and desperate and her hands fist against the blankets as she fights the urge to reach for them.

 

Natasha nods against Maria’s shoulder. “Yes. Yes, please, yes.”

 

They are the only ones Natasha will be this vulnerable for, and Melinda recognizes Natasha’s honest need as the gift that it is. She bends to press a kiss to Natasha’s back and lightly trail her fingertips across Maria’s leg. “God I love you two,” Melinda murmurs quietly.

 

Melinda straightens and she meets Maria’s eyes as she begins to push the dildo into Natasha. Natasha’s breathing stalls as Melinda pulls back out before pushing in deeper. Her fingers curl around Natasha’s hips as she fucks Natasha slowly. Melinda gives her a chance to adjust to the toy before pulling almost all the way out of her. And before Natasha can complain Melinda snaps her hips forward.

 

Natasha cries out as Melinda’s pelvic bone grinds against her ass. She pants against Maria’s neck, whimpering against Maria’s skin as Melinda withdraws and repeats the motion. Melinda begins to fuck Natasha in earnest, and she continues to hold Maria’s gaze while she does. Natasha curses, broken syllables falling from her lips as she gets closer to coming, and Maria makes the most beautiful sound of desperation that Melinda has ever heard.

 

“Fuck,” Melinda groans. She fucks Natasha harder and grinds her clit against the base of the dildo with each thrust.

 

Natasha comes quietly. She gasps as her entire body vibrates with pleasure, and Melinda strokes Natasha’s hip gently as she slows her thrusts. Maria tilts her head to kiss Natasha’s temple. Her hands come up to caress Natasha’s trembling arms and Melinda doesn’t stop her. Natasha needs the physical contact when she comes. She needs the reminder that they’re there; that they have her, and it’s ok for her to let go.

 

Melinda waits for the soft whimper that tells her Natasha is starting to recover, and she adjusts her hand. Melinda continues to fuck Natasha slowly even as she circles Natasha’s clit with her middle finger. Natasha presses her face into Maria’s neck with a strangled cry as Melinda manipulates her cilt.

 

Maria cups the back of Natasha’s head. “One more, love,” Maria almost pleads. “Come again for us.” There is no mistaking the need in Maria’s voice, and Natasha whimpers helplessly.

 

“Oh,” Natasha gasps as Melinda shifts the angle of her hand. “Oh, fuck..”

 

“There?” Melinda rasps, and Natasha nods soundlessly.

 

It doesn’t take long. A few more strokes and a bit more pressure against Natasha’s clit and she comes so hard that she almost collapses on top of Maria. Melinda grinds against the toy, painfully close to her own orgasm, and Maria’s hips buck uselessly.

 

Natasha’s lips part and she bites into Maria’s neck without warning. She bites almost hard enough to break the skin, and Maria’s hips lift off of the bed as she comes with a stuttering cry. The sound Maria makes is what does it, and Melinda presses into Natasha as she comes with a deep moan. Melinda tips forward, barely managing to catch herself with her hands against the mattress before she falls across Natasha’s back.

 

“Christ,” Melinda murmurs as she tries to catch her breath. Natasha hums in quiet agreement and Maria manages a soft groan.

 

Melinda spends a few seconds pressing kisses to the parts of Natasha’s back that she can reach before she straightens and pulls out of Natasha. Natasha relaxes on top of Maria with a contented sigh while Melinda shimmies out of the harness. She drops it over the side of the bed, too tired to deal with cleanup tonight. Besides, she thinks as she stretches out along Maria’s side, she has more important things to worry about right now.

 

“Is she already asleep?” Melinda asks as she rejoins them, amusement heavy in her voice.

 

Maria smiles as she strokes Natasha’s back. “You wore her out.”

 

“I’m awake,” Natasha mumbles unconvincingly, and Melinda and Maria both laugh.

 

“Go to sleep, love,” Melinda tells her. She tucks a stray curl behind Natasha’s ear. “Though I do need to borrow your pillow.”

 

Natasha kisses Maria’s chest before turning her head to press a kiss to Melinda’s wrist. “Love you,” she murmurs to them, and she rolls off of Maria. Natasha burrows under the blankets and is asleep again within moments. Melinda and Maria watch her for a few seconds to make sure she’s alright before they refocus on one another.

 

Melinda plucks at the hem of Maria’s shirt. “Let me see.” Maria hesitates for just a second, and Melinda’s gaze softens. “Please?”

 

Maria sighs as she sits up and pulls her shirt over her head. Melinda traces Maria’s bruises with trembling fingers and Maria watches her carefully. “I’m alright,” Maria reminds her.

 

“I’m going to _murder_ them,” Melinda promises fiercely.

 

“Hey,” Maria cups her face and pulls Melinda’s attention away from the patchwork of bruises on her chest. “I’m fine, Mel, honestly. It just.. hurts a little.”

 

Instead of responding Melinda leans forward and trails her tongue along the edge of a bruise under Maria’s breast. Maria’s breath catches and she relaxes back against the mattress with a quiet _oh._ Melinda spends long minutes kissing and licking and (occasionally) biting her way across Maria’s chest. She caresses Maria’s bruises with painfully gentle touches until Maria is writhing desperately beneath her.

 

“Tell me what you need,” Melinda murmurs as she helps Maria out of her underwear.

 

“Just you,” Maria groans, “just you and Natasha.”

 

“You have us,” Melinda reminds her gently. “We aren’t going anywhere.”

 

Maria gasps as Melinda’s hand dips between her legs. “Promise me.”

 

Melinda leaves a trail of kisses across Maria’s chest as she moves her fingers through Maria’s arousal. “We should make it official. You two seem convinced that this is going to fall apart at any minute.”

 

“Because you’ve never worried you might lose us,” Maria scoffs even as her hips rise to meet Melinda’s fingers.

 

Melinda goes still for a moment. “It’s my greatest fear,” she admits quietly, and Maria knows that she isn’t talking about one of them leaving.

 

Maria opens her mouth to say something, but Melinda cannot keep talking about this. Maria may be fine, but it’s a fucking miracle that the past couple of days left behind only cuts and bruises. For a brief moment they hadn’t been sure if Maria was still alive, and it isn’t a feeling Melinda can handle reliving right now. So she cheats. Melinda pushes into Maria with two fingers, and whatever Maria was going to say is lost in a soft cry. “You’re going to wake Natasha,” Melinda murmurs as she crooks her fingers rapidly.

 

“You.. little shit,” Maria manages. Melinda smiles, unrepentant as she moves her fingers faster, and Maria gasps as her back arches away from the bed. “ _Fuck!_ ”

 

“Shhh,” Melinda soothes, and she dips her head to trace the edge of Maria’s collarbone with her tongue.

 

Maria wraps her arms around Melinda’s shoulders. She presses her face into her neck in an attempt to quiet the desperate sounds Melinda pulls from her. Melinda glances over Maria’s shoulder and smirks when she finds Natasha watching them intently.

 

Maria’s hips roll against Melinda’s hand as she trembles.

 

“God you feel so good,” Melinda groans, and Maria whines softly.

 

Maria muffles her cry against Melinda’s throat as she comes, and Melinda presses kisses to Maria’s skin as she works her through it. Natasha stretches to kiss Maria’s shoulder and stroke her stomach, and Maria groans deeply. “We were trying not to wake you.”

 

Natasha laughs. “You both suck at being quiet.” She stretches a bit more to capture Melinda’s lips with her own. “Not that I’m complaining.”

 

“It sounds like complaining,” Melinda teases, and she pulls away before Natasha can bite her.

 

Maria settles onto her back and Natasha and Melinda curl up on either side of her. She runs her hands across their backs and strokes her fingers through their hair and thinks that she doesn’t deserve to be this happy.

 

“Were you serious?” Maria asks eventually.

 

Melinda doesn’t need to ask what she means. “Yeah. I was.”

 

“What are we serious about?” Natasha, who was asleep at the time, _does_ need to ask.

 

“Mel wants to ‘make it official’.”

 

Natasha blinks. She presses more firmly into Maria’s side and tightens her grip on Melinda’s hand and doesn’t say anything for a few minutes. Maria rests her head against Natasha’s and Melinda strokes Natasha’s hand with her thumb, and they both wait.

 

“Really?” Natasha asks after a few minutes.

 

“Am I the only one who assumed this was forever?” Melinda’s tone is teasing but they can both hear the serious edge of uncertainty in her words. “Because if so, holy fuck do we need to have a conversation about what we’re doing here.”

 

Maria squeezes her tightly. “I think this is just what happens when three emotionally damaged idiots try to build something real together. We’re all waiting for the other two to change their minds.”

 

“I figure you’re going to come to your senses eventually,” Natasha says quietly. “But I’d really, really like forever. If you’re offering.”

 

“I’m offering,” Melinda murmurs. “Maria?”

 

“You know, practically everyone in SHIELD has a running bet about this.” Maria tells them.

 

“Not at all what I was asking.”

 

“Yes,” Maria answers, “obviously it’s yes.”

 

“We can be in Vegas in less than five hours,” Natasha suggests.

 

“We aren’t getting married in **Vegas** ,” Melinda insists without missing a beat.

 

Natasha and Melinda continue to argue about the validity of Vegas weddings and Maria laughs quietly. She falls asleep with a smile on her face as she listens to their teasing argument, and she conveniently forgets to mention exactly how it is that she knows their relationship is being bet on by their fellow agents, or how much money Melinda’s spur of the moment proposal just cost her.

  
(Maria had been so sure that _she_ would be the one to eventually propose to them.)

**Works inspired by this one:**

  * [Fill Me Up](https://archiveofourown.org/works/12645573) by [Tigerkid14](https://archiveofourown.org/users/Tigerkid14/pseuds/Tigerkid14)




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